CDP Composite (1xEVDO)

CDP Composite shows the Code Domain Power trace data for the composite signal (combined code layers and channels). Code Domain Power (CDP) is an analysis of the distribution of signal power across the set of code channels normalized to the total signal power. If the Measurement Interval is greater than one, all slots within the Measurement Interval are averaged together to produce the CDP Composite results.

CDP Composite trace data results are computed from data specified by the Measurement Interval and Offset parameters. The forward link CDP composite results are for the specified Analysis Channel. When Preamble is selected by Analysis Channel, CDP measurements only exist for cases where the preamble length is detected to be 1024 chips.

View CDP trace data as absolute power by clearing the Normalize IQ Traces check box (MeasSetup > 1xEV-DO Demod Properties > Advanced tab).

Display Format

The data is shown in a multi-color format that assigns a unique color to each code layer and related active code channels. This makes it easy to visually identify and distinguish the active code channels (Walsh Code Number) for a given code layer (Walsh Code Length). The colors are also user definable (see Display Preferences > Color tab).

For CDP and CDE trace data displays with separate I/Q channel trace bars, to position the Marker to the desired Code Layer/Channel bar, click in close proximity to the horizontal bar that indicates the value of the code channel being measured.

The y-axis shows the power level and the x-axis shows the Walsh Code Number (code channel). The x-axis annotation and marker location are based on the lowest symbol rate (ksym/sec), or equivalently, the highest Walsh Code length. The channels can also be reordered so that all related code channels are displayed adjacent to each other (see Code Order).

$image\1xEVDO_CDP.jpg$

This example shows the Channel 1 Composite CDP display (code order = bit reversed) for a reverse link signal, Trace A Marker shows the following:

Symbol Rate:	307.2 Ksym/s
Walsh Code Length:	4
Walsh Code Number	2
IQ branch	Q branch
Power Level:	-0.417 dB
Asterisk *:	The asterisk (*) indicates that the marker is positioned on an active channel

Use the CDP Layer trace data display to view only one code layer (Walsh Code Length) at a time.